S.G. Barroso

Leptin association with erythrocyte sodium content in obesity-related hypertension

Insulin resistance is frequently associated with obesity-related hypertension. Leptin resistance and increased plasma leptin levels are frequent companions in this association. To examine whether in obesity hypertension with insulin resistance, plus hyperleptinemia, the sodium content of erythrocyte (Naie) reflects a positive sodium balance related to the physiological loss of leptin in sodium reabsorption, we studied a group of obese hypertensive patients, and a group of lean normotensive subjects. In obese hypertensives, fasting glucose, insulin and the insulin resistance index were higher as compared to the lean individuals (107.0 ± 4.1 mg/dl, 10.2 ± 1.4 pU/ml and 2.94 ± 0.52, respectively, vs 98.7 ± 4.1 mg/dl, 7.22 ± 1.33 U/ml, and 1.79 ± 0.16, respectively, p < 0.002). Both the leptin/BMI 2 index as well as the Naie were significantly higher in the obese hypertensive group as compared to control group (1.9± 0.21 vs 1.25 ± 0.27, respectively p < 0.01, and 12.5 ± 0.51 vs 10.7 ± 0.5 mEq/ml/cell, respectively p < 0.05). In obese hypertensives the leptin/BMI 2 index was significantly associated with DBP (r= = 0.41, p < 0.04), MBP (r= 0.44, p < 0.03), Naie (r = 0.41, p < 0.05) and age (r = 0.43, p = 0.03). We conclude that in obese hypertensive patients Naie is increased reflecting a state of positive sodium balance. In these patients, the elevated circulating leptin concentrations were one of the main regulators of the content of sodium in erythrocytes.

Leptina, Elo Adicional na Fisiopatologia da Pré-eclâmpsia?

Purpose: to study in primigravid adolescents the behavior of serum leptin levels during the evolution of normal pregnancy, comparing the results with those obtained from preeclamptics. Methods: prospective, longitudinal study conducted in 15 normotensive pregnant adolescents and 5 preeclamptic adolescents. Serum leptin levels (ng/mL) were determined by radioimmunoassay. Blood pressure was measured by the oscilometric method by using DINAMAP 1846. Patients were evaluated in two different gestational periods: between the 21st and 30th week and between the 31st and 40th week. The ratio leptin/body mass index (BMI) was used to correct changes observed in BMI throughout gestation. Preeclamptic pregnant patients were diagnosed when the blood pressure was ³140/90 mmHg, proteinuria >300 mg/24 h and when arteriolar spasm was present in the optic fundi. Results: there was a trend towards an elevation of serum leptin at the end of pregnancy in both groups although more pronounced in preeclamptic patients. In pregnant normotensive patients serum leptin increased from 11.9±1.20 (21st to 30th week) to 13.9±2.23 ng/mL (31st to 40th week), and in preeclamptic from 11.9±1.20 to 17.6±4.565 ng/mL. In preeclamptic patients the BMI increased significantly in the period from the 21st to 30th week when compared to the period between the 31st and 40th week: 21.5±0.8 vs 27.4±1.7 kg/m2, p<0.05. In normotensive these values were maintained stable: 24.9±1.5 vs 25.1±1.00 kg/m2. At the end of gestation the ratio leptin/BMI was significantly higher in preeclamptics: 0.56±0.06 (21st to 30th week) vs 0.70±0.15, p<0.05. The values of the ratio leptin/BMI in normotensive pregnants varied from 0.44±0.02 between the 21st and 30th week to 0.41±0.04 between the 31st to 40th week. In normal pregnants there was a direct and significant correlation between the levels of leptin and BMI in both periods of pregnancy: r = 0.7, p<0.004 (31st to 40th ) vs r = 0.94, p<0.0001 (31st to 40th week). These correlations were lost in preeclamptic patients in both gestational periods. Conclusion: the higher concentrations of leptin and leptin/BMI ratio observed when preeclamptics were compared with normotensive patients, in both gestational periods, suggest a leptin resistance pattern in preeclampsia.